The present invention relates optical communications, and, more particularly, to Quality of Service QoS-aware unified control protocol for optical burst switching in software defined optical networks.
The following background documents are discussed in the present application: [VVokkarane] V. Vokkarane, “Design and Analysis of Architecture and Protocols for Optical Burst-Switched Networks,” Ph.D. Dissertation, UT-Dallas, June 2004; [[PPedroso]] P. Pedroso, J. Perello, M. Klinkowski, D. Careglio, S. Spadaro, and J. Sole-Pareta, “A GMPLS/OBS Network Architecture Enabling QoS-Aware End-to-End Burst Transport,” Proc. of HPSR, 2011; [SDas] S. Das, G. Parulkar, and N. McKeown, “Unified Packet and Circuit Switched Networks,” Proc. of IEEE GLOBECOM Workshop, pp. 1-6, December 2009; [DZhang] D. Zhang. L. Liu, L. Hong, H. Gou, T. Tsuritani, J. Wu, and I. Morita, “Experimental Demonstration of OBS/WSON Multi-Layer Optical Switched Networks with an OpenFlow-based Unified Control Plane,” Proc. of ONDM, pp. 1-6, April 2012; [Ychen] Y. Chen, M. Hamdi, and D. Tsang, “Proportional QoS over OBS Networks,” Proc. of IEEE GLOBECOM, pp. 1510-1514, December 2001.
Among the optical circuit, packet, and burst switching technologies, optical circuit switching offers course switching granularity, and has large round trip latency in a connection setup. On the other hand, optical packet switching has a large buffer requirement, complicated control, and synchronization requirements [VVokkarane]. Optical Burst Switching (OBS) is a promising technology for future optical networks, which offers an intermediate solution by leveraging benefits of packet switching such as statistical multiplexing over high-speed optical transmission. OBS offers finer switching granularity of traffic with lower complexity and higher resource efficiency.
Generalized Multi-protocol Label Switching (GMPLS) is one such distributed unified control plane protocol that has been extensively investigated to support optical burst switching in the previous studies [PPedroso]; however, this protocol is overly complicated and fragile. In spite of an existence of mature GMPLS technologies, network operators are reluctant in deploying such technologies in commercial networks. Furthermore, GMPLS is defined just over existing IP/MPLS networks and may not be capable of incorporating everything in a homogeneous protocol suite [SDas]. Thus, GMPLS may not offer unified control plane infrastructure.
Recently, Software-Defined Network (SDN) architecture is introduced in which control planes are extracted from the data planes of physical hardware, and these control planes of heterogeneous devices are aggregated in the centralized controller. A controller communicates with the data planes of devices through an open protocol such as OpenFlow. The protocol extracts a common set of functionalities for heterogeneous switching granularity across multiple layers. The control plane decisions taken by the controller are represented in terms of a set of actions, rules, and policies, and those are cached in the data planes of physical hardware. Thus, the same data plane can support heterogeneous protocols and switching granularity. On the other hand, the controller abstracts the common-map of data planes across multiple layers while hiding the implementation details, and thus, offers virtualization. Therefore, SDN architecture enables control protocols that can simultaneously manage, control, and operate multiple layers with heterogeneous switching granularity. Such architecture enables more flexibility in hardware selections, shorter time to implement new technologies and products, more efficient and reliable automatic unified control, and optimized utilization of network resources.
An optical burst switching protocol mainly requires four key operations; burst assembling, burst routing, burst scheduling, and control packet signaling. In distributed protocols, burst assembling, burst routing, and burst scheduling operations are performed at every edge node independently based on the local network state information, and control packet signaling is performed hop-by-hop in a distributed manner.
On the other hand, in software-defined networks, burst assembling, burst routing, and scheduling operations can be performed at the centralized controller to optimize the network performance using the global network state information. The control plane decisions taken at the controller can be cached simultaneously in the programmable data plane using OpenFlow protocol. Thus, open issues in realizing OBS over SDN are how to perform burst assembling, burst routing, and burst scheduling operations in a centralized controller, and how to enhance the OpenFlow protocol to support OBS over SDN, such that network performance is enhanced.
Looking at prior efforts by others, in [DZhang], OpenFlow protocol is enhanced to support OBS over SDN, and the realization of OBS over SDN is demonstrated through experiments. However, the burst assembling and burst scheduling operations are performed at edge nodes using legacy protocols in the proposed solution in [DZhang]. The burst assembling, routing, and scheduling solutions are not yet investigated in the OpenFlow based SDN architecture.
Accordingly, there is a need for QoS-aware unified control protocol for optical burst switching in software defined optical networks.